Tops of my prints get ruined

[Mike&Mr.Stevens]

Sometimes the tops of my prints get ruined. I am running a H 1.1 on repetier with marlin firmware. 0.2 layer height. Any tips on how to fix this?

[foshon]

Looks too hot IMHO, I would slow the printer down to 50% when it gets about 3/4 up the head.

[dsnettleton]

Looks too hot IMHO, I would slow the printer down to 50% when it gets about 3/4 up the head.

I agree that it's too hot. I always thought slowing the print speed down would increase heat buildup, though. Am I wrong?

[foshon]

Looks too hot IMHO, I would slow the printer down to 50% when it gets about 3/4 up the head.

I agree that it's too hot. I always thought slowing the print speed down would increase heat buildup, though. Am I wrong?

In my experience allowing the lower layers to cool a bit before I lay more down seems to cool everything down. A fan would accomplish much the same thing.

[Mike&Mr.Stevens]

Looks too hot IMHO, I would slow the printer down to 50% when it gets about 3/4 up the head.

I agree that it's too hot. I always thought slowing the print speed down would increase heat buildup, though. Am I wrong?

In my experience allowing the lower layers to cool a bit before I lay more down seems to cool everything down. A fan would accomplish much the same thing.

I do have a 50mm fan on the back. It kicks in occasionally, I don't know what settings to put in under that cooling section in slic3r, so I left it default. How do I go about making it so it slows and cools after the first 75% of the print? Here is a picture of my setup and my best print so far.

You guys are really helping, thank you!

[Jimustanguitar]

I'm getting similar results and will be experimenting with a cooling fan this weekend. Between slowing down and using a fan, I hope to get this figured out.

Let me know what works for you, and I'll share my results too.

[foshon]

I'm getting similar results and will be experimenting with a cooling fan this weekend. Between slowing down and using a fan, I hope to get this figured out.

Let me know what works for you, and I'll share my results too.

If you are using Slic3r there is a special section for controlling the fan. It can be activated any time the layer will take under "x" seconds to complete. The time needed to complete smaller layers or in the case of a tapering model can be calculated by figuring the circumference in mm of the desired "on" layer and using movement speed to get a time reference. As an alternative, you can turn the fan on for the entire print and raise the nozzle temp 5-15 degrees.

I switch my bed fan on manually when I think it is needed. I realize this doesn't help an unattended print session, but it works great for items where quality is a large concern.

[Eaglezsoar]

I assume from all the talk about fans that all of you are using PLA?

[foshon]

I assume from all the talk about fans that all of you are using PLA?

From the way the top of that knight looks, it wouldn't make a difference.

[Jimustanguitar]

I'm printing ABS. This is what my heat issues look like:

[img]http://i.imgur.com/h0YfBy2.jpg[/img]

[img]http://i.imgur.com/uo2E8Hl.jpg[/img]

[foshon]

That looks more like speed to me Jim. In the first pic you can see circular layers that were pulled inward from poor/no adhesion.

[Mike&Mr.Stevens]

I use ABS. Me and PLA don't get along.